Method and apparatus for stablizing flow to sharp edges orifices

Abstract

A method and apparatus for stablizing flow to sharp edged orifices by placing a convergent section upstream of the orifice.

I claim: 
     
       1. An improved fluid jet cutting nozzle of the type utilizing a jeweled orifice downstream of a collimating chamber, the improvement comprising: a convergent cone upstream of the jeweled orifice adjacent thereto for collimating the fluid flow to said orifice, the minimum diameter of the cone being larger than the diameter of the orifice; and,   means for mounting said convergent cone in said collimating chamber.   
     
     
       2. A nozzle as in claim 1 wherein the diameter of the downstream end of said convergent cone is larger than the diameter of the jewel orifice. 
     
     
       3. A nozzle as in claim 2 wherein the length of said cone is at least 1/2 of the length of said collimating chamber. 
     
     
       4. A method for controlling turbulence upstream of a jewel cutting orifice in a fluid jet cutting tool comprising the steps of: producing a stream of high pressure fluid;   passing said stream through a convergent cone section to remove turbulence; and,   passing said converged stream through a jewel orifice adjacent the convergent cone section which has a diameter less than the minimum diameter of the convergent cone section to produce a coherent fluid cutting jet.   
     
     
       5. A method as in claim 4 further comprising the step of forcing said converged stream to pass a sharp step. 
     
     
       6. A method for increasing the coherent length of a fluid jet emerging from the jewel orifice of a fluid jet cutting tool, comprising the steps of: producing a stream of high pressure fluid; and,   passing said stream through a convergent cone section adjacent the orifice, the minimum diameter of the convergent cone section being greater than the diameter of said orifice.   
     
     
       7. An improved fluid jet cutting nozzle of the type utilizing a jeweled orifice downstream of a collimating chamber, the improvement comprising: a convergent cone upstream of the jewel orifice for collimating the fluid flow to said orifice, the minimum diameter of the downstream end of the convergent cone being larger than the diameter of the orifice, the length of said cone being at least 1/2 of the length of said collimating chamber; and means for mounting said convergent cone in said collimating chamber.